Ethanol can be produced using grains, such as corn, which are renewable resources. Presently, the majority of ethanol-producing biorefineries in the United States are dry-grind corn biorefineries, and it is estimated that the present ethanol production capacity of such biorefineries runs into the billions of gallons each year. Co-products of the ethanol biorefining process are distillers dried grains and distillers dried grains with solubles. Based on current production rates of ethanol from dry-grind ethanol plants, approximately 40 million tons of DDGS are produced in the United States annually.
Over the past few decades, achieving an ethanol product from grain-based biorefineries that is both commercial viable and truly renewable has proven challenging. Two of the more significant hurdles are: 1) the cost of grain-based ethanol production; and 2) the energy input to output ratio of grain-based ethanol production processes. As is easily appreciated, these two problems are intertwined. Grain-based ethanol production has historically required significant and costly input of fossil fuels (e.g., natural gas) to drive the biorefining process. Moreover, the amount of fossil fuel that has been historically required to drive grain-based ethanol production is costly, particularly so as the cost of natural gas and other fossil fuels increases.
One of the ways by which the effective cost of grain-based ethanol production can be reduced is the sale of commercially valuable co-products of the biorefining process. DDGS are co-products of grain-based ethanol production processes that have recognized commercial value. In particular, DDGS are sold as a livestock feed supplement. Because it is primarily the starch of the grain that is consumed in the production of ethanol, the DDGS remaining after fermentation and distillation contain nutritionally valuable fiber, protein and fat. Relative to raw grain, DDGS may even be considered a superior feed, as they contain concentrated amounts of fiber, protein and fat, together with a significantly reduced amount of starch. In addition, DDGS are considerably less expensive than some feeds of comparable nutritional value.